12V and 5V from 10 Nimh cells
 

I have two identical 5 cell nimh packs and I will use them in series to obtain 12V. It is easy to have the 6V for radio receiver and servos using only plus and minus from one of the battery but I don't want to unbalance the load on the two packs. Using two diodes I can connect the two packs in parallel too obtaining 5V, 6V minus the diode voltage.
I wonder if it is a good solution or if it is better using a cc-bec with 12V in input and 6V in output. What do you think is the most efficient solution ?
Obviously two diodes cost less than a cc-bec... but servo torque is greater with 6V...

Thanks
Filippo